organize const eval tests

Author: HKalbasi

crates/hir_ty/src/consteval.rs

@@ -87,14 +87,14 @@ impl Display for ComputedExpr {
         match self {
             ComputedExpr::Literal(l) => match l {
                 Literal::Int(x, _) => {
-                    if *x >= 16 {
+                    if *x >= 10 {
                         write!(f, "{} ({:#X})", x, x)
                     } else {
                         x.fmt(f)
                     }
                 }
                 Literal::Uint(x, _) => {
-                    if *x >= 16 {
+                    if *x >= 10 {
                         write!(f, "{} ({:#X})", x, x)
                     } else {
                         x.fmt(f)
@@ -156,6 +156,7 @@ pub fn eval_const(
 ) -> Result<ComputedExpr, ConstEvalError> {
     let expr = &ctx.exprs[expr_id];
     match expr {
+        Expr::Missing => Err(ConstEvalError::IncompleteExpr),
         Expr::Literal(l) => Ok(ComputedExpr::Literal(l.clone())),
         &Expr::UnaryOp { expr, op } => {
             let ty = &ctx.expr_ty(expr);
@@ -339,6 +340,9 @@ pub fn eval_const(
                     Ok(r.clone())
                 }
                 ValueNs::ConstId(id) => ctx.db.const_eval(id),
+                ValueNs::GenericParam(_) => {
+                    Err(ConstEvalError::NotSupported("const generic without substitution"))
+                }
                 _ => Err(ConstEvalError::NotSupported("path that are not const or local")),
             }
         }
@@ -433,7 +437,7 @@ pub(crate) fn const_eval_query(
 ) -> Result<ComputedExpr, ConstEvalError> {
     let def = const_id.into();
     let body = db.body(def);
-    let mut infer = db.infer_query(def);
+    let infer = &db.infer(def);
     let result = eval_const(
         body.body_expr,
         &mut ConstEvalCtx {
@@ -442,7 +446,7 @@ pub(crate) fn const_eval_query(
             exprs: &body.exprs,
             pats: &body.pats,
             local_data: HashMap::default(),
-            infer: &mut infer,
+            infer,
         },
     );
     result
@@ -473,3 +477,6 @@ pub(crate) fn eval_to_const<'a>(
     };
     usize_const(eval_usize(expr, ctx))
 }
+
+#[cfg(test)]
+mod tests;

crates/hir_ty/src/consteval/tests.rs

@@ -0,0 +1,148 @@
+use base_db::fixture::WithFixture;
+use hir_def::{db::DefDatabase, expr::Literal};
+
+use crate::{consteval::ComputedExpr, db::HirDatabase, test_db::TestDB};
+
+use super::ConstEvalError;
+
+fn check_fail(ra_fixture: &str, error: ConstEvalError) {
+    assert_eq!(eval_goal(ra_fixture), Err(error));
+}
+
+fn check_number(ra_fixture: &str, answer: i128) {
+    let r = eval_goal(ra_fixture).unwrap();
+    match r {
+        ComputedExpr::Literal(Literal::Int(r, _)) => assert_eq!(r, answer),
+        ComputedExpr::Literal(Literal::Uint(r, _)) => assert_eq!(r, answer as u128),
+        x => panic!("Expected number but found {:?}", x),
+    }
+}
+
+fn eval_goal(ra_fixture: &str) -> Result<ComputedExpr, ConstEvalError> {
+    let (db, file_id) = TestDB::with_single_file(ra_fixture);
+    let module_id = db.module_for_file(file_id);
+    let def_map = module_id.def_map(&db);
+    let scope = &def_map[module_id.local_id].scope;
+    let const_id = scope
+        .declarations()
+        .into_iter()
+        .find_map(|x| match x {
+            hir_def::ModuleDefId::ConstId(x) => {
+                if db.const_data(x).name.as_ref()?.to_string() == "GOAL" {
+                    Some(x)
+                } else {
+                    None
+                }
+            }
+            _ => None,
+        })
+        .unwrap();
+    db.const_eval(const_id)
+}
+
+#[test]
+fn add() {
+    check_number(r#"const GOAL: usize = 2 + 2;"#, 4);
+}
+
+#[test]
+fn bit_op() {
+    check_number(r#"const GOAL: u8 = !0 & !(!0 >> 1)"#, 128);
+    check_number(r#"const GOAL: i8 = !0 & !(!0 >> 1)"#, 0);
+    // FIXME: rustc evaluate this to -128
+    check_fail(
+        r#"const GOAL: i8 = 1 << 7"#,
+        ConstEvalError::Panic("attempt to run invalid arithmetic operation".to_string()),
+    );
+    check_fail(
+        r#"const GOAL: i8 = 1 << 8"#,
+        ConstEvalError::Panic("attempt to run invalid arithmetic operation".to_string()),
+    );
+}
+
+#[test]
+fn locals() {
+    check_number(
+        r#"
+    const GOAL: usize = {
+        let a = 3 + 2;
+        let b = a * a;
+        b
+    };
+    "#,
+        25,
+    );
+}
+
+#[test]
+fn consts() {
+    check_number(
+        r#"
+    const F1: i32 = 1;
+    const F3: i32 = 3 * F2;
+    const F2: i32 = 2 * F1;
+    const GOAL: i32 = F3;
+    "#,
+        6,
+    );
+}
+
+#[test]
+fn const_loop() {
+    check_fail(
+        r#"
+    const F1: i32 = 1 * F3;
+    const F3: i32 = 3 * F2;
+    const F2: i32 = 2 * F1;
+    const GOAL: i32 = F3;
+    "#,
+        ConstEvalError::Loop,
+    );
+}
+
+#[test]
+fn const_impl_assoc() {
+    check_number(
+        r#"
+    struct U5;
+    impl U5 {
+        const VAL: usize = 5;
+    }
+    const GOAL: usize = U5::VAL;
+    "#,
+        5,
+    );
+}
+
+#[test]
+fn const_generic_subst() {
+    // FIXME: this should evaluate to 5
+    check_fail(
+        r#"
+    struct Adder<const N: usize, const M: usize>;
+    impl<const N: usize, const M: usize> Adder<N, M> {
+        const VAL: usize = N + M;
+    }
+    const GOAL: usize = Adder::<2, 3>::VAL;
+    "#,
+        ConstEvalError::NotSupported("const generic without substitution"),
+    );
+}
+
+#[test]
+fn const_trait_assoc() {
+    // FIXME: this should evaluate to 0
+    check_fail(
+        r#"
+    struct U0;
+    trait ToConst {
+        const VAL: usize;
+    }
+    impl ToConst for U0 {
+        const VAL: usize = 0;
+    }
+    const GOAL: usize = U0::VAL;
+    "#,
+        ConstEvalError::IncompleteExpr,
+    );
+}

crates/hir_ty/src/tests/simple.rs

@@ -1749,6 +1749,18 @@ fn main() {
     );
 }
 
+#[test]
+fn const_eval_array_repeat_expr() {
+    check_types(
+        r#"
+fn main() {
+    const X: usize = 6 - 1;
+    let t = [(); X + 2];
+      //^ [(); 7]
+}"#,
+    );
+}
+
 #[test]
 fn shadowing_primitive_with_inner_items() {
     check_types(